• Journal of Conservation Science
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• v.9 no.1
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• pp.40-47
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• 2000

Dimension stability was examined after PEG pretreatment and post freeze-drying treatment in order to determine the PEG(#3350) concentration and solvent for pre-treatment of freeze-drying of highly-degraded waterlogged ash woods(Fraxinus spp.; ca. 5,700 BP) excavated from peat lands at Pyungtack, Kyounggi-do. At the low concentration (<30-40%) of PEG soaking in both water and t-butanol, the weight increases abruptly, but at high concentration (>50%) gradually, consequently, taking longer treatment time. PEG loading was higher in t-butanol solution than in water. However, the best dimesional stability was obtained from freeze-drying after lower PEG solution (40% in water) soaking. Low dimensional stability, found in the samples treated with higher PEG solutions (60%-70% in t-butanol), might come from incomplete freezing and excess PEG absorbing moisture. The samples air-dried after 70% PEG treatment had collapse defects. In conclusion, the use of low concentration (about 40% in water) PEG solution was the most suitable pretreatment for freeze drying of highly-degraded waterlogged ash woods.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.221-227
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• 1995

White clover (Trifolium repens L) gives rise to either weak persistence or overdominance in the pastures. To get information on grazing method to surmount the problem, the experiment was done to measure the effect of infrequent, frequent and their alternations on harvest yield and morphological characteristics of the clover. Individual plants of Regal, Louisiana S-l, Grasslands Huia, and Aberystwyth S184 were grown in 22cm plastic pot containing a 2： 1： 1 soil： sand： Peat moss mixture for 27 days after transplanting 50-day seedlings raised on 3cm pots, and then their all fully expanded leaves are trimmed. Defoliation treatments were forced every 1 (CC, frequent), 4 week(RR,infrequent) or their alternations(CR, RC) after 8 weeks from the trimming. To analyze the treatment effects, plants were sampled on 4, 8, 12, and 16 weeks after the trimming. Harvest yield of infrequent defoliation (RR) was higher than that of frequent defoliation (CC). Leaf area and no. of leaves per plant, petiole length and stolon length per plant, moreover, showed the similar result to the yield but stolon length and leaf area per g were reverse. The alternation of infre-quent and then frequent defoliation (RC) had greater yield than that of their reverse (CR) although both alternations showed intermediate ones compared to CC and RR. Morphological characteristics, furthermore, related to the clover leaf were immediately changed by alternations of defoliation inter-val(RC and CR) while those done to the stolon were lasted longer thereafter(RC and CR). Harvest yields in RC and CR were positively correlated to leaf area and no. of leaves or stolon length per plant but negatively done to leaf area and stolon length per g. It is concluded that weak persistence or overdominance of white clover in pasture can be controlled by alternation of infrequent and then frequent defoliation or reverse.

• KSBB Journal
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• v.16 no.3
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• pp.286-289
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• 2001

A beterotrophic Pseudomonas putida B2 was used to treat of hydrogen sulfide containing gas. The experimental approach involved operating two indentical bench-scale biofilters with media consisting of a mixture of peatmoss, perlite and granular activated carbon(GAC). One column was seeded with Pseudomonas putida B2 and the other was left unseeded. The biofilter was operated for 16 days under EBRT for 20-40 sec, at a temperature of 25-30$^{\circ}C$ and a hydrogen sulfide concentration of 40-190 ppm. The biofilter inocculated with P.putida B2 exhibited high hydrogen sulfide removal efficiency, average of 95%, at a gydrogen sulfide concentration of 40-190 ppm (flow rate 3.6 L/min). However, at a shock loading of 190 ppm the biofiter showed a removal efficiency of 78.9% and the control only showed a removal efficiency of 31.6%. The critical load of this biofilter was 14.83 g/㎥hr, and the critical load of the control column was 4.93 g/㎥hr. These results suggest that P. putida B2 has the potential to be used as a $H_2S$ removal agent in a biofilter.

• Journal of the Korean Geotechnical Society
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• v.30 no.10
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• pp.67-80
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• 2014

The thickness of permafrost in Eastern Siberia is from 200 to 500 meters. The seasonally frozen layer can vary from 0 to 4m depending on ground temperature and its location. The shear wave velocity varies from 80m/s in summer to 1500m/s in winter depending on soil type. When melted, large impedence will occur due to the difference between the shear wave velocity of seasonally frozen soil and that of permafrost layer. Large displacement may occur at the boundary of the melted and the frozen layer, and this phenomenon should be considered in a seismic design. In this research, one-dimensional equivalent linear analyses were performed to investigate the effects of the seasonally frozen layer on ground amplification characteristics. Soil profiles of Yakutsk and Chara in Eastern Siberia were selected from geotechnical reports. 20 recorded ground motions were used to evaluate the effect of input motions. As the thickness of seasonally frozen layer and the difference in the shear wave velocity increases, the amplification is shown to increase. Peat, very soft organic soil widely distributed throughout Eastern Siberia, is shown to cause significant ground motion amplification. It is therefore recommended to account for its influence on propagated motion.

• Korean Journal of Environmental Agriculture
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• v.14 no.1
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• pp.82-87
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• 1995

The standardization of test procedures and reproducibility of the toxicity data are prerequisite for the toxicity testing with the earthworm culturing in the laboratory. No in-depth study on culturing conditions of earthworms has been conducted in Korea, even of massive cultural practice is common for composting and production of biochemicals. The earthworms, Lumbricus rubellus and Eisenia foetida, were cultured in three kinds of artificial soil substrates(I, II and III) based on the OECD Guideline, which consist of different ratios of components (sand, sphagnum peat and kaolinite), and fed with a mixture of grain powders. During the period of culturing, the body weight and reproduction parameters were measured. L. rubellus showed the best results for increasing body weight and cocoon production in the artificial soil substrate(I) compared with E. foetida. The cocoon production was significantly high in both species cultured in the artificial soil substrate(I) among the three kinds of soil substrates, but the cumulative cocoon production of L. rubellus was 11 cocoon per worm compared with 3.7 cocoons per worm of E.foetida. L. rubellus, therefore, was more prolific than E. foetida in these culture schemes. The cumulative mortality in both species was less than 10%, and the number of juvenile worms per cocoon ranged from 1.5 to 2.3 and thus did not show any relationships with soil substrates or species. From these data, the culture of L. rubellus in the laboratory could be standardized, but for E. foetida, further study would be necessary to establish the optimal growth conditions in the laboratory.

• Journal of Bio-Environment Control
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• v.11 no.3
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• pp.108-114
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• 2002

Cellular glass foam (CGE), the reprocessed glass, has a possibility as a component of vegetative propagation media of floricultural crops due to the its excellent air and water permeability, similar to that of perlite. An experiment was conducted to evaluate the rooting and growth thereafter of Kalanchoe blossfeldiana ‘Gold Strike’in media containing various volume ratios of granular rockwool, peat-moss, CGF and perlite. The particle size of CGF and perlite was 2.0~4.0mm and 1.2~4.0mm, respectively. Cuttings were rooted in a fog tunnel with a mean temperature of 18.2$^{\circ}C$ and RH of 66.7％ under a long day regime (14 h per day light period). Height, length of the longest root, stem diameter, no. of leaves, leaf area, percentage of rooted cuttings, shoot and root fresh weights, shoot and root dry weights, total chlorophyll concentration and physicochemical properties were measured. Cuttings rooted 100% in all treatments. Physicochemical properties in CGF and perlite-containing media showed little differences. The growth of rooted plants in the CGF-containing media was similar or rather superior to that in perlite-containing media. Consequently, CGF has a possibility as a vegetative propagation medium of Kalanchoe. To make wider commercial use of CGF, more demonstrative experiments and analyses are necessary.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.2
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• pp.55-58
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• 2004

The objective of this study was to get information about water retention characteristics of horticultural substrates used in Korea determined by European standard method. Water retention curves were prepared at water volume (v/v, %) in relation to -10 cm, -50 cm, -100 cm water pressure head. Water retention curves showed different properties depending upon the type, the place of origin, particle size, and manufacturing processes of substrates. Peat and coir had easily available water content in the range of 30-40% and showed high water holding capacity, water buffering capacity, and aeration for plant growth. However, bark, sawdust and rice hull showed low water holding capacity about below 10%. The easily available water content of perlite and clay ball was low about 0.1-13.8%, whereas that of vermiculite and rockwool granulate was high about 25.9-52.0%. Understanding water retention characteristics of growing substrates is very important in cstablisliing optimum condition for plant growth. Further study on water retention curves for more substrates, mixture and growing media is needed.

• Reproductive and Developmental Biology
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• v.29 no.2
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• pp.69-73
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• 2005

The hematopoietic growth factor erythropoietin (EPO) is required for the maintenance, proliferation, and differentiation of the stem cells that produce erythrocytes. To analyse the biological activity of the recombinant human EPO (rec-hEPO), we have cloned the EPO cDNA and genomic DNA and produced rec-hEPO in the CHO cell lines. The growth and differentiation of EPO-dependent human leukemic cell line (F36E) were used to measure cytokine dependency and in vitro bioactivity of rec-hEPO. MIT assay values were increased by survival of F36E cells at 24h or 72h. The hematocrit and RBC values were increased by subcutaneous injection of 20 IU (in mice) and 100IU(in rats) rec-hEPO. Hematocrit values remarkably increased at $13.2\%$ (in mice) and $12.2\%$ (in rats). The pharmacokinetic behavior with injection of 6 IU of rec-hEPO remained detectable after 24 h in all mice tested. The highest peat appeared at 2h after injection. The long half-life of rec-hEPO is likely to confer clinical advantages by allowing less frequent dosing in patients treated for anemia. These data demonstratethat ree-hEPO produced in this study has a potent activity in vivo and in vitro. The results also suggest that biological activity of ree-hEPO could be remarkably enhanced by genetic engineering that affects the potential activity, including mutants with added oligosaccharide chain and designed to produce EPO-EPO fusion protein.

• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.56-60
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• 2000

A study was performed to determine the maintenance conditions of the earthworm, Lumbricus rubellus, for the acute toxicity test. To fine out climatic and soil conditions, the earthworms were maintained in artificial soil consisting of sand, clay mineral and peat at different levels of conditions for 14 days. Lumbricus rubellus led to an increase of biomass at temperature $22{\pm}2^{\circ}C$, soil pH $7.0{\pm}1$ and moisture 40%. And four fungicides were tested for acute toxicities to Lumbricus rubellus, according to the optimum condition. The test earthworms were exposed to each pesticide with various concentration gradients. After 14 days, the number of surviving earthworms and their weight alteration during the test period was determined. The 14-day $LC_{50}$ values for the Lumbricus rubellus, of carbendazim, benomyl, thiophanate-methyl and thiabendazole were determined to be 59, 53, 64 and 36 mg/ kg soil dry weight, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.1
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• pp.44-52
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• 1996

Humic substances of 17 organic fertilizers available on the market were the objects of study. The list of ingredients for formulation of them comprised fish meal. bone meal, oil-cakes, brewer's grains, peat, sawdust, wood bark, zeolite, soil conditioner, live-stock droppings, amino acid fermentation byproduct, chaff, limestone and others. Humic and fulvic acids were isolated from those substances and given chemical and spectroscopic analyses. Nutritional values of the organic fertilizers showed big diversity. Humification of organic matter was incomplete for some of the fertilizers as indicated by a high C/N ratio. Extractable humic acid percentage was higher, in general, than that of fulvic acid. Also the relative content of humin increased with advanced humification. Total acidity was closely related to phenolic hydroxyl groups. Relationships between carboxyl and hydroxyl groups. and carboxyl and alcoholic hydroxyl groups were very significant. Ultraviolet and visible light absorption spectra of humic and fulvic acids were substantially similar. The types of humic acids were B. P, and Rp. Two humic acids of the 17 samples belonged to B type. 3 to P type and all the rest to Rp type.